code: def test_hmean_iou(self):
      metric = HmeanIOUMetric(prefix="mmocr")
      metric.process(None, self.predictions)
      eval_results = metric.evaluate(size=2)
  
      precision = 3 / 5
      recall = 3 / 4
      hmean = 2 * precision * recall / (precision + recall)
      target_result = {
          "mmocr/precision": precision,
          "mmocr/recall": recall,
          "mmocr/hmean": hmean,
      }
      self.assertDictEqual(target_result, eval_results)
  
file_path: mmocr/tests/test_evaluation/test_metrics/test_hmean_iou_metric.py
imports: import unittest
  import numpy
  import torch
  from mmengine.structures import InstanceData
  from mmocr.evaluation import HmeanIOUMetric
  from mmocr.structures import TextDetDataSample
label_desc: Use image node_id 2 for calling the TestHmeanIOU obj's underlying member method code with example usage: obj.test_hmean_iou() without return types